Lubrizol Genetics, Inc.

The Lubrizol Corporation

John Shine

Kieran F Scott

Barry G Rolfe

Hauke Hennecke

John M Watson

Peter Schofield

This invention provides useful promoters from the R. trifolii nifH gene for the construction of recombinant molecules to regulate foreign genes for expression under desired conditions. In particular, the promoters act to control expression of the foreign genes within root nodules formed by rhizobial bacterial strains in symbiotic combination with host plants. A rhizobium diagnostic segment (RDS) is also provided comprising a DNA segment found at more than one location in rhizobia, the RDS being species-specific, and detectable by DNA hybridization under stringent conditions. A recombinant plasmid comprising a RDS and a bacterial strain containing the plasmid are provided. Methods are provided for identifying species and strains of field isolates of Rhizobium, using RDS's. One RDS exemplified comprises 5' sequences from the R. trifolii nifH gene.

Rhizobial diagnostic probes and rhizobium trifolii nifH promoters

The nifH promoter regions of Bradyrhizobium japonicum and Bradyrhizobium sp. (parasponia) have been sequenced and found to be significantly homologous. Recombinant DNA molecules comprising foreign genes under the control of such promoters are provided. Rhizobial species containing such recombinant constructions, either in plasmids or integrated into the genome, are provided. These are especially useful for expressing desired foreign genes within root nodules.

nifH promoters of Bradyrhizobium

The nifD promoter regions of Bradyrhizobium japonicum and Bradyhizobium sp. (Parasponia) have been sequenced and found to be significantly homologous. Recombinant DNA molecules comprising foreign genes under the control of such promoters are provided. Rhizobial species containing such recombinant constructions, either in plasmids or integrated into the genome, are provided. These are especially useful for expressing desired foreign genes within root nodules.

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Sydney, Australia

John Shine